This Contract provides statistical support to the Division of Cancer Treatment's Gastrointestinal Tumor Study Group, a cooperative group engaged in intensive clinical studies on patients with gastrointestinal cancer. The specific activities required are provide review of proposed studies to ensure that studies can be controlled from a data acquisition viewpoint; devise and implement a data processing program to readily retrieve and analyze all data collected by Group clinicians; aid Group clinicians in collection of data; participate in the writing and statistical design of all clinical protocols; issue interim progress reports on current studies; analyze ongoing studies to determine unusual clinical occurences, identify unforseen difficulties with new studies, and initiate necessary revisions to therapy; and conduct data analyses of completed studies. Speical statistical analyses may also be requested.